To set up Android Jelly Bean 4.2 on a smartphone, follow the onscreen instructions that appear with the system update notification received on the phone. For the setup on a personal computer, having a virtual box is necessary.
To get Android Jelly Bean 4.2 on the computer, first download the latest version of the Oracle VM virtual box and then install it. Also, download the Android 4.2 image. Then, open the virtual box and select new. A dialog box appears in which you have to enter a name of your choice. Select the type as Linux and the version as other Linux.
Select next to proceed with the steps. In the next dialog box that pops up, feed in the memory size, and click on next. Select to create a virtual hard drive, then select the virtual device interface and a fixed or dynamically allocation based on individual choice. Next, create the virtual drive.
Select virtual device and click on settings. Choose the storage tree as empty in the storage section and select Android 4.2 iso-extension file in the attribute section. Start the virtual device, and install the Android x86 to the hard disk.
Select create/modify partition and then choose a new primary partition and select write. Quit writing once complete, and install the Android. Remove the live iso-extension file from the virtual box and reboot into the Android Jelly Bean 4.2.